The above findings provide additional evidence that a large proportion of individuals with schizophrenia are able to provide research informed consent and that their ability to do so can be improved through the use of a brief and practical intervention. There are several additional and important points to make about the current study. First, consistent with previous research, individuals with schizophrenia demonstrated relatively strong decisional capacity even without remediation, although not at the level attained by participants in the healthy comparison group. Second, the schizophrenia group showed significant improvement and was not significantly different from the healthy comparison group in any aspect of decisional capacity following the intervention. This was the case even though the intervention was very brief and was conducted with a group of individuals who were, on average, in the borderline range (seventh percentile) with regard to global neuropsychological functioning. Last, the degree of improvement among the subset of schizophrenia group participants we studied was moderately large in size (Cohen's d = 0.6), and all of the schizophrenia group participants were ultimately able to demonstrate adequate understanding of the hypothetical research scenario, as measured by the ESC.
The above findings add to the existing data indicating that individuals with schizophrenia are able to benefit from attempts to improve decisional capacity.6, 10–11
Specifically, the current study serves most closely as a replication of work by Dunn and coauthors, who also used a relatively brief intervention that included simplified, computerized presentation of consent form information and postintervention testing that involved corrective feedback.10–11
It is worth noting that those studies involved the assessment of decisional capacity within the context of an actual consent process as participants were being enrolled into an ongoing research protocol. Although such an approach increases the ecological validity of their findings, the protocol under consideration was relatively basic and did not involve a treatment trial or complex concepts such as randomization, double blinding, placebo control, and side effects. The current study, although reliant on a hypothetical research scenario, indicates that individuals with schizophrenia are able to benefit from an enhanced consent process, even when faced with a much more complex research protocol.
A common criticism of this type of study is that participants are certain to show improvement because, in the intervention process, the investigators are merely “teaching to the test.” Indeed, such a statement is true to some degree, but it should not be levied as criticism, because the goal of the intervention is to improve decisional capacity within the context of the specific research protocol in question, not improvement of more general cognitive ability. Therefore, such a situation is altogether different from having a research participant study the same word list repeatedly and then interpreting improved recall of the list as evidence of generally improved memory function. Furthermore, when using instruments such as the MacCAT-CR, examiners are careful to have participants respond in their own words as much as possible, as opposed to verbatim repetition of what they have been told. This increases the likelihood that improved scores do reflect actual improvement in understanding.
This study has several limitations. The fact that the groups did not differ significantly on any aspect of decisional capacity following the intervention must be interpreted cautiously, given our relatively modest sample size. We are also unable to comment specifically on what aspect of the intervention we used was most helpful, as all participants in the schizophrenia group received both the standardized computer presentation and the individualized corrective feedback components. It should also be reiterated that individuals in the comparison group did not receive the intervention, so it is not known how much they would have improved if they had. Nonetheless, we consider them to be a valid comparison group because healthy people do not typically experience any form of enhanced consent process in actual research, and the high baseline MacCAT-CR scores earned by these individuals in the current study indicate that they would not have required such intervention. It is also important to note that the schizophrenia group received a second administration of the MacCAT-CR. Given that this involves additional disclosure of consent form information, it is conceivable that this contributed to that group's improved scores, in addition to the intervention described above. Finally, the type of intervention used in the current study did not address all aspects of decisional capacity but, rather, focused mainly on understanding and, to a lesser degree, appreciation.
The current study and others like it have provided convincing evidence that a large percentage of individuals with psychiatric illness are able to make informed decisions regarding participation in research and that those individuals who initially lack this capacity may benefit significantly from enhanced consent procedures. One of the next challenges in this area of research will involve developing new strategies to improve not only basic understanding of research protocols but also the ability to reason with this information in as organized and efficient a manner as possible. Such research will move the field closer to the ideal balance of providing adequate subject protection while also avoiding the unnecessary exclusion of those individuals who have difficulty with traditional consent procedures.